This invention relates generally to brackets for use in orthodontics and more particularly to brackets with high retentive forces and an apparatus for fabricating such brackets.
An orthodontic bracket is one of appliances to be used in orthodontics, i.e. for reforming an irregular set of teeth. In orthodontic operations, brackets are fixed by adhesives to adjacent teeth and bound together by connecting wires or thin rods to impose a corrective force upon a particular tooth to be reformed.
In general, the orthodontic bracket is composed of two parts, i.e. a main body to which wires or rods are engaged, and a welding flange or base from which the main body is projecting and which is to be welded or bonded to the tooth surface. Heretofore, the main body was welded or otherwise secured to the base to make up the orthodontic bracket.
Such combined brackets, however, have many defects and disadvantages, such as
(I) separation of the main body from the base due to heavy stresses imposed by fastened wires; PA1 (II) difficulties and inaccuracy in bonding the main body onto the base; and PA1 (III) peeling off from the base of a net member, which is fixed to the undersurface of the base in order to reinforce retentive forces between the teeth and the brackets.
In view of these circumstances, I have provided a method for fabricating a bracket in which a main body and a base plate are originally and essentially integral with each other by cutting and bending operations of a unitary and continuous rod material into a shape of integral main body and base plate (Japanese patent application No. 174157/1982).
In the above-mentioned method, the undersurface of the base is preferably formed with rough surfaces so as to strengthen the retentive forces of the adhesives against the undersurface of the base. By such method, however, the retentive forces between the base and the adhesive has not been found sufficiently strong.